Alan Ladd and Betty Field in 1949’s “The Great Gatsby,” which has never been released on video. Photo:

Disney’s “Song of the South’’ hasn’t been legally available in any form in the US since its last theatrical release in 1986, but you can find it with a few clicks of a (non-Mickey) mouse.

The racially controversial, part-animated 1946 musical that gave the world “Zip-a-Dee-Doo-Dah’’ has resided in its entirety on YouTube, apparently without protests from the Mouse House’s lawyers, since at least 2008.

Most classic-era movies on YouTube have long been in the public domain, but a much smaller number, like “Song of the South,’’ are still in copyright. Sometimes tangled rights issues block a video release — as is the case with the noir-inflected 1949 version of “The Great Gatsby’’ starring Alan Ladd, which briefly surfaced on TV around 1980 and has never been released by its owner Universal on video.

There are no such legal obstacles with “Song of the South.” Cartoon segments from the film have been available on video from Disney since the 1980s. The studio is much more sensitive, though, about the live-action portions, which even back in the 1940s were criticized by the NAACP for “the impression it gives of an idyllic master-slave relationship” — though the happy, singing Uncle Remus (played by James Baskett, who won a special Oscar for “his able and heart-warming characterization”) is technically a sharecropper after the Civil War.

“I just felt there are elements to the film, while it was a relatively good film, that wouldn’t be in the best interest of our shareholders to bring it back, even though there would be some financial gain,” Disney CEO Robert Iger told shareholders in 2011. “I just don’t feel that it’s right for us to use company resources to make it available.’’

Some of those who have long lobbied for the film’s release believe that Disney, which used to zealously guard the film’s copyright, has quietly decided not to block efforts to distribute it on YouTube or through other channels.

“It’s curious,’’ says Christian Willis, who has exhaustively chronicled the film’s travails at songofthesouth.net for more than a decade. “They were really heavily enforcing [the copyright], and any clips they could find were being quickly pulled down from YouTube.

“People used to be prosecuted for selling bootlegs, but as far as I can tell that hasn’t happened since 2004,” Willis says. “You can find bootleg DVDs [mostly derived from licensed foreign laserdisc releases] on dozens of pages at eBay. Maybe it’s a way for Disney to ease pressure on them from people demanding to see it.”

Jim Korkis, an unofficial Disney historian who recently authored the book “Who’s Afraid of Song of the South?’’ theorizes the studio may be testing the waters for an eventual release by letting it circulate in bootleg form to gauge reaction (which has been mostly positive, though a significant number still regard it as racist).

“Disney has digitally transferred this title, and it could be made available on Blu-ray in the snap of a finger,’’ Korkis says. “But it’s a no-win situation for them. What makes ‘Song of the South’ different than [the racially problematic] ‘Birth of a Nation’ or ‘Gone With the Wind’ is that it’s primarily a children’s movie, and providing any amount of historical context isn’t going to help.’’

Meanwhile, even the upcoming release of a new version of “The Great Gatsby’’ starring Leonardo DiCaprio hasn’t spurred a home video release for the 1949 edition with Ladd, which has been sitting unchallenged on YouTube for at least the past couple of years.

Apparently the film’s owner, Universal Pictures, hasn’t been able to able to come to terms with F. Scott Fitzgerald’s heirs to renew the underlying literary rights to this film, which was acclaimed during a rare theatrical showing at the Noir City Film Festival last year in Los Angeles.

Another much sought-after title by classic-film fans, “Christmas Holiday’’ (1944), was uploaded to YouTube in December 2008.

Never shown on US TV, much less released on video here by Universal, this musical noir stars hugely popular singer-actress Deanna Durbin as a thinly disguised prostitute in New Orleans who has problems with her homicidal estranged husband (Gene Kelly).

Literary rights are likely the culprit — same as for “Once in a Lifetime’’ (1932). A hilarious version of a Broadway play by George S. Kaufman and Moss Hart whose portrayal of Hollywood’s panic at the coming of sound anticipates “Singin’ in the Rain,’’ it hasn’t been officially seen since its only TV airing on PBS in 1971. But you can find this gem on YouTube in its entirety.

UPDATE (APRIL 18): YouTube has blocked the upload of “Song of the South’’ previously embedded in this article at Disney’s request as part of a crackdown. Details here.